Inorganic spherical absorption pigments

Abstract

The present invention relates to inorganic spherical absorption pigments which have a bimodal particle-size distribution, at least one color-providing layer and a final SiO 2 layer, and to the use thereof in paints, coatings, printing inks, security printing inks, plastics, ceramic materials, glasses, as tracers, in cosmetic formulations and for the preparation of pigment preparations and dry preparations.

1. A spherical absorption pigment, which comprises:
 a component A comprising spherical particles having a particle size of 1-100 nm which are coated with one or more color-providing layers and, over the color-providing layer(s), a layer of SiO 2    
 
       and
 a component B comprising spherical particles having a particle size of 0.5-50 μm which are coated with one or more color-providing layers and, over the color-providing layer(s), a layer of SiO 2 .  
 
     
     
       2. A spherical absorption pigment according to  claim 1 , wherein the spherical particles for at least one of component A and component B are SiO 2  beads, TiO 2  beads, nanoscale metal particles, polymer beads, glass beads and/or hollow glass beads. 
     
     
       3. A spherical absorption pigments according to  claim 1 , wherein the spherical particles for both component A and component B are SiO 2  beads. 
     
     
       4. A spherical absorption pigment according to  claim 1 , wherein at least one color-providing layer for at least one of component A and component B is a layer of a metal oxide, metal sulfide, metal nitride, metal oxynitride, metal or mixture thereof. 
     
     
       5. A spherical absorption pigment according to  claim 4 , wherein at least one color-providing layer is TiO 2 , ZrO 2 , SnO 2 , ZnO, BiOCl, Ce 2 O 3 , FeO(OH), Fe 2 O 3 , Fe 3 O 4 , TiFe 2 O 5 , Cr 2 O 3 , Fe 4 [Fe(CN) 6 ] 3 , a titanium sub-oxide, a titanium oxynitride, pseudobrookite, titanium nitride, CoO, CO 3 O 4 , VO 2 , V 2 O 3 , NiO, CoAl 2 O 4 , BiVO 4 , Ce 2 S 3 , MoS 2 , Al, Fe, Cr, As, Au, Pt, Pd or mixture thereof. 
     
     
       6. A spherical absorption pigment according to  claim 1 , wherein component A and/or component B comprises one, two, three, four, five or seven color-providing layers. 
     
     
       7. A spherical absorption pigment according to  claim 4 , wherein component A and/or component B comprises one, two, three, four, five or seven color-providing layers. 
     
     
       8. A spherical absorption pigment according to  claim 5 , wherein component A and/or component B comprises one, two, three, four, five or seven color-providing layers. 
     
     
       9. A spherical absorption pigment according to  claim 6 , wherein component A and/or component B comprises one, two or three color-providing layers. 
     
     
       10. A spherical absorption pigment according to  claim 1 , wherein the color-providing layer(s) in component A and component B are each one or more metal-oxide layers. 
     
     
       11. A spherical absorption pigment according to  claim 10 , wherein the metal oxide layers are TiO 2 , Fe 2 O 3 , Fe 3 O 4 , FeO(OH), an iron titanate, pseudobrookite or a mixture thereof. 
     
     
       12. A spherical absorption pigment of  claim 1 , wherein color-providing layer(s) for component A and component B are the same. 
     
     
       13. A spherical absorption pigment according to  claim 1 , wherein component A and component B are mixed in a weight ratio of from 1:10 to 10:1. 
     
     
       14. A spherical absorption pigment according to  claim 1 , wherein at least one of component A and component B additionally has an outer protective layer in order to increase the light, temperature and/or weather stability. 
     
     
       15. A process for the preparation of a spherical absorption pigment according to  claim 1 , which comprises mixing the spherical particles of components A and B with one another in suspension, and coating the spherical particles by wet-chemical processes by hydrolytic decomposition of metal salts in aqueous and/or organic solvents and/or by means of CVD and/or PVD processes or by reduction from an aqueous solution of metal salts. 
     
     
       16. A paint, coating, printing ink, security printing ink, plastic, ceramic material, glass, tracer, or cosmetic composition comprising a spherical absorption pigment of  claim 1 . 
     
     
       17. A cosmetic composition comprising a spherical absorption pigment of  claim 1 . 
     
     
       18. A dry pigment composition comprising a spherical absorption pigment of  claim 1 .